Disorders of the eye, such as cataract, glaucoma, age-related macular degeneration and diabetes-related retinopathy as well as retinal changes and retinal detachments are increasing, partially owing to higher life expectancy. To treat these and other eye disorders a vitrectomy is often indicated, during which it must be ensured that damage to the retina is minimal. One precautionary measure consists in removing the internal limiting membrane (ILM) and any epiretinal membranes from the retina during the vitrectomy in order to relieve the assumed intravitreal tensile forces on the macula. This is achieved by peeling the membranes away from the retina using forceps. For the surgeon, it is necessary to be able to distinguish as accurately as possible between the retina and the membrane to be peeled away. To this end, the membranes to be peeled away should be made visible by means of staining as specifically as possible. Dyes suitable for staining have to meet many criteria. They must be biocompatible and non-toxic and must not damage the cells; they should be water-soluble, should stain as specifically as possible and should be easily flushed out again. Dyes and methods for staining the said membranes have already been described, but they are not yet completely satisfactory.
Thus, U.S. Pat. No. 7,014,991 describes a method of staining ocular structures in the human eye, wherein the staining takes place by injection of the dye indigotindisulfonate into the appropriate tissue. However, indigotindisulfonate is cytotoxic.
Other dyes, such as Brillant Blue G, Brilliant Blue R, Patent Blue V or methylene blue, have also been proposed for use in the eye.
During vitrectomy or surgical intervention, the eye socket is flushed with a flushing solution. Now, one problem with the dye solutions known hitherto consists in the fact that the dye solution is dispersed, diluted and flushed out by the flushing solution. This has several disadvantages. On the one hand, the surgeon's view is clouded if the flushing solution is coloured. On the other hand, more dye solution is needed than would be required only for staining the membrane.
In order to overcome this disadvantage it has already been proposed to add a thickener, such as e.g. hyaluronic acid, to the dye solution, which increases the viscosity of the dye solution. The increase in viscosity is intended to reduce the transfer of the dye into the flushing solution as a result of decreased mobility, i.e. through steric hindering, so that more of the dye reaches the area of the membrane to be stained. However, the high viscosity of the dye solution means that it is now difficult for the dye to transfer out of this on to the membrane, so that again the need for dye solution is greater than the amount that would be required only for staining the membrane.
The object of the invention was therefore to provide a preparation which can specifically stain membranes, and in particular can selectively stain the membranes to be removed, such as the internal limiting membrane (ILM) and/or epiretinal membranes (EMR), in the human or animal eye, which can be applied readily, migrates to the membrane immediately after application and disperses there without staining the flushing solution too strongly. In addition, a preparation is to be provided which leads to neither local irritations nor damage to the retina, is not cytotoxic but is well tolerated.
This object is achieved by a preparation as defined in the claims, particularly in claim 1.
The subclaims contain advantageous developments.